Application of biomarkers and oil fingerprinting for genetic classification of oil families and prediction of oil migration pathways in Nuraly field

This paper presents the interpretation of the results of biomarker analysis and oil fingerprinting of all producing wells (36 samples) of Nuraly field for genetic typing and fluid communication assessment within the field, followed by predicting the hydrocarbon migration pathways. According to the biomarker study, it was revealed that the oils of central and western Nuraly have genetically different origins, and the petroleum accumulation in the southern part of West Nuraly was formed by the continuous secondary migration of HC from the northeastern and northwestern directions. Oils from central Nuraly field have higher thermal maturity and lower density than those of western Nuraly do. The thermal maturity of samples from Central Nuraly decreases from the northeastern part of Nuraly towards the southwestern part, which may also attest to hydrocarbon migration pathways. The presence of gas caps in the northeastern part of Central Nuraly may be due to their high thermal maturity.

Application of NSO compounds in the research of hydrocarbon migration direction in the Wangjiagang area of the Dongying sagin the Bohai Bay Basin

The determination of hydrocarbon migration direction is an important part in the study of petroleum accumulation in petroliferous basins, and plays an important role in guiding oil and gas exploration activity. Despite their relatively low content in petroleum, the polar nitrogen-, sulphur-and oxygen- containing compounds (collectively referred to as NSO compounds) have great potential in characterizing the hydrocarbon migration process. A series of crude oils along hydrocarbon migration pathway were selected and analysed using GC×GC/TOFMS and GC-MS in the Wangjiagang area of the Dongying sag. Total concentration of NSO compounds and other related parameters are determined to verify the role of different parameters in indicating hydrocarbon migration. Our research result shows that the total amount of NSO compounds, 1-/3-MC ratio, 1,8-/2,7-DMC ratio, 4-/1-MDBF ratio and 2,4-/1,4-DMDBT ratio changes grandully with the increase of migration distances. Thus, these parameters can be applied as effective migration direction indicators in study area. Some other parameters may not be suitable for the identification of hydrocarbon migration direction in the study area.